[DirectX][MC] Add MC support for DXContainer

DXContainer files resemble traditional object files in that they are
comprised of parts which resemble sections. Adding DXContainer as an
object file format in the MC layer will allow emitting DXContainer
objects through the normal object emission pipeline.

Differential Revision: https://reviews.llvm.org/D127165

1 files changed, 26 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 52bf48b..1c0c711 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -26,6 +26,7 @@
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCLabel.h"
 #include "llvm/MC/MCSectionCOFF.h"
+#include "llvm/MC/MCSectionDXContainer.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSectionGOFF.h"
 #include "llvm/MC/MCSectionMachO.h"
@@ -145,6 +146,7 @@ void MCContext::reset() {
 
   // Call the destructors so the fragments are freed
   COFFAllocator.DestroyAll();
+  DXCAllocator.DestroyAll();
   ELFAllocator.DestroyAll();
   GOFFAllocator.DestroyAll();
   MachOAllocator.DestroyAll();
@@ -176,6 +178,7 @@ void MCContext::reset() {
   COFFUniquingMap.clear();
   WasmUniquingMap.clear();
   XCOFFUniquingMap.clear();
+  DXCUniquingMap.clear();
 
   ELFEntrySizeMap.clear();
   ELFSeenGenericMergeableSections.clear();
@@ -838,6 +841,29 @@ MCSectionSPIRV *MCContext::getSPIRVSection() {
   return Result;
 }
 
+MCSectionDXContainer *MCContext::getDXContainerSection(StringRef Section,
+                                                       SectionKind K) {
+  // Do the lookup, if we have a hit, return it.
+  auto ItInsertedPair = DXCUniquingMap.try_emplace(Section);
+  if (!ItInsertedPair.second)
+    return ItInsertedPair.first->second;
+
+  auto MapIt = ItInsertedPair.first;
+  // Grab the name from the StringMap. Since the Section is going to keep a
+  // copy of this StringRef we need to make sure the underlying string stays
+  // alive as long as we need it.
+  StringRef Name = MapIt->first();
+  MapIt->second =
+      new (DXCAllocator.Allocate()) MCSectionDXContainer(Name, K, nullptr);
+
+  // The first fragment will store the header
+  auto *F = new MCDataFragment();
+  MapIt->second->getFragmentList().insert(MapIt->second->begin(), F);
+  F->setParent(MapIt->second);
+
+  return MapIt->second;
+}
+
 MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
   return *new (MCSubtargetAllocator.Allocate()) MCSubtargetInfo(STI);
 }